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Increasing Concentrations (increasing + concentration)
Selected AbstractsFeeding value of total mixed ration silage with spent mushroom substrateANIMAL SCIENCE JOURNAL, Issue 2 2010Chuncheng XU ABSTRACT Six wethers were used in a digestibility experiment arranged as replicated 3 × 3 Latin square to evaluate the nutritive value of total mixed ration (TMR) silages that were made from ensiling of TMR containing 0, 6.5 and 13.0% (dry matter basis) of spent mushroom substrate (SMS) for 45 days (treatments denoted as CSMS, LSMS and HSMS, respectively). The amount of SMS replaced the same amount of timothy hay in the respective TMR. All TMR were well preserved as indicated by their low pH, low ammonia-N and high lactic acid contents. Increasing levels of SMS in the TMR silage quadratically reduced (P < 0.05) nutrient digestibility with the exception of ether extract. The difference of total digestible nutrients and digestible energy contents between LSMS and CSMS TMR silage were less than those between LSMS and HSMS. Increasing concentration of SMS in the ration tended to decrease content of total volatile fatty acids in rumen fluid but increased the ratio of acetate to propionate and pH. The study suggests that a SMS level of 6.5% in the diet DM can be recommended for silage based TMR. [source] Acute and chronic toxicity of nitrate to fathead minnows (Pimephales promelas), ceriodaphnia dubia, and Daphnia magnaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2000George Scott Abstract Increasing concentrations of nitrate in surface water and groundwater are becoming a worldwide concern, yet little information has been published on toxicity of nitrate to common organisms used for toxicity testing. The acute and chronic toxicity of nitrate (NO3 -N) to Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas was investigated in 48-h to 17-d laboratory exposures. The 48-h median lethal concentration (LC50) of nitrate to C. dubia and D. magna neonates was 374 mg/L NO3 -N and 462 mg/L NO3 -N. The no-observed-effect concentration (NOEC) and the lowest-observed-effect concentration (LOEC) for neonate production in C. dubia were 21.3 and 42.6 mg/L NO3 -N, respectively. The NOEC and LOEC values for neonate production in D. magna were 358 and 717 mg/L NO3 -N, respectively. The 96-h LC50 for larval fathead minnows (P. promelas) was 1, 341 mg/L NO3 -N. The NOEC and LOEC for 7-d larval and 11-d embryo-larval growth tests were 358 and 717 mg/L NO3 -N, respectively. Additional exposure of breeding P. promelas and their fertilized eggs to nitrate did not increase susceptibility further. The LC50 values for all species tested were above ambient concentrations of nitrate reported for surface water. However, the LOEC for C. dubia was within the range of concentrations that could be found in streams draining areas under extensive agricultural cultivation. [source] Influence of complexation with chloride on the responses of a lux-marked bacteria bioassay to cadmium, copper, lead, and mercuryENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000Charoon Sarin Abstract The toxicity of a heavy metal in solution to a microorganism depends not only on its concentration but also on pH and the concentrations of any aqueous complexing ligands in the microorganism's environment. This paper reports on the use of different inorganic resuscitation media and effect of the chloride ion, Cl,, on the bioluminescence response of a bacterial biosensor, Escherichia coli HB101 (pUCD607), to four metals: Cd, Cu, Hg, and Pb. The toxicity tests were conducted at pH 4, using 0.1 M KNO3 as resuscitation medium and adding KCl to investigate effect of Cl, concentration. The species distributions of metals as a function of Cl, concentration were calculated using GeoChem-PC. Resuscitation in 0.1 M KC1 gave significantly higher light output than that in 0.1 M KNO3, demonstrating that Cl, in the resuscitation medium has a direct effect on the bioluminescence response of the E. coli biosensor. Increasing concentrations of Cl, ions increased the toxicity of Hg, apparently because of the formation of HgCl,3, and increased the toxicity of Pb because of PbCl+ formation. The toxicity of Cu decreased at high Cl, concentrations as free Cu2+ decreased, in accordance with the free ion model. Concentrations of Cl, had no significant effect on the toxicity of Cd. This study clearly demonstrates that the chloro-complexes of some heavy metals can be toxic and, for Pb and Hg, more toxic than the free ion. [source] ,1 -antitrypsin prevents polymorphonuclear leucocyte-elastase effects on spermatozoa qualityINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2010J. Leßig Summary Elevated levels of polymorphonuclear leucocyte (PMN)-derived elastase, which is suggested as marker for inflammations in the male genital tract, correlate well with spermatozoa deterioration. PMN elastase caused a time- and concentration-dependent (up to a elastase concentration of 0.5 ,g/mL) externalization of phosphatidylserine and intercalation of propidium iodide on human spermatozoa. There are apparently a limited number of target sites for elastase on spermatozoa surface, because the further enhancement of elastase amount did not fasten alterations in spermatozoa parameters. Analysis of flow cytometry data revealed that most spermatozoa were in a necrotic state after an exposure with elastase for 22 h. Some apoptotic cells were only detected at shorter incubation periods. Seminal plasma prevented in a concentration-dependent manner the PMN elastase-mediated loss of vitality of spermatozoa. We detected by blotting techniques large amounts of ,1 -antitrypsin in seminal plasma. This antiproteinase is known to inactivate elastase at inflammatory sites. Increasing concentrations of ,1 -antitrypsin prevented gradually spermatozoa deterioration induced by elastase. Thus, ,1 -antitrypsin contributes to an efficient protease/antiproteinase balance in seminal plasma. A disturbed balance will promote the development of chronic inflammations which can also be the reason for male infertility problems. [source] Oxidation of diclofenac sodium by diperiodatoargantate(III) in aqueous alkaline medium and its determination in urine and blood by kinetic methodsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 6 2010P. N. Naik The kinetics and oxidation of diclofenac sodium (DFS) by diperiodatoargentate(III) (DPA) in alkaline medium at 298 K and at a constant ionic strength of 0.60 mol dm,3 were studied spectrophotometrically. The oxidation products were [2-(2,6-dicloro-phynylamino)-phenyl]-methenol and Ag(I), identified by LC-ESI-MS and IR spectral studies. The reaction between DFS and DPA in alkaline medium exhibits 1:1 stoichiometry. The reaction is first order in [DPA] and has a less than unit order dependence each in [DFS] and [alkali]. Increasing concentrations of IO,4 retard the reaction. The active species of DPA proposed to be monoperiodatoargentate(III), and a mechanism is suggested. The rate constants involved in the different steps of the mechanism were determined and are discussed. The activation parameters with respect to a rate-limiting step of the mechanism were determined. The thermodynamic quantities were also determined. Using the oxidation of DFS by DPA, DFS was analyzed by kinetic methods in urine and blood sample. The proposed method enables DFS analysis in the range from 5.0 × 10,5 to 5.0 × 10,3 mol dm,3. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 336,346, 2010 [source] Effect of different chemical compounds as coadjutants of 4-hexylresorcinol on the appearance of deepwater pink shrimp (Parapenaeus longirostris) during chilled storageINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 11 2008Oscar Martínez-Alvarez Summary Different chemical compounds (kojic acid, cumic acid, phytic acid, sodium metabisulphite, magnesium carbonate, sorbic acid and different protease inhibitors) were used as coadjutants in 4-hexylresorcinol (4-HR)-based melanosis-inhibiting formulas tested for inhibiting melanosis in pink shrimp (Parapenaeus longirostris). The experiment was performed on board ship. Increasing concentrations of 4-HR delayed the occurrence of melanosis during storage. However, 4-HR could not prevent the appearance of a yellow-greenish colouration in the cephalothorax that diminishes the consumer acceptability of shrimps. The incorporation of protease inhibitors (ethylenediaminetetraacetic acid, disodium dihydrogen pyrophosphate, iodoacetic acid, egg white and phenylmethylsulphonyl fluoride) into the 4-HR-based mixtures improved the acceptability after storage, suggesting that protease activity post-mortem contributes to the reduction in the final acceptability of crustaceans. [source] Allelopathic Effects of Parthenium hysterophorus Extracts on Seed Germination and Seedling Growth of Eragrostis tefJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2002T. Tefera The present study was conducted to investigate the allelopathic effects of Parthenium hysterophorus weed on seed germination and seedling growth of tef. Flower, stem, root and leaf aqueous extracts of Parthenium at 0, 1, 5, and 10 % concentrations were applied to determine their effect on tef seed germination and seedling growth under laboratory conditions. Increasing concentrations of aqueous extracts of Parthenium from leaf and flower inhibited seed germination and complete failure of seed germination was recorded when the extract concentration from the leaf part was 10 %. In contrast, aqueous extracts from stem and root had no effect on tef seed germination. Roots appeared more sensitive to allelopathic effect than shoots. Extracts from flower, root and stem had a stimulatory effect on shoot length at all concentration levels, as against an inhibitory effect of leaf extracts. Root extracts at low concentration (1 %) greatly promoted root length but aqueous extracts from leaf and flower inhibited root length. [source] Influence of replacing brewers' grains with green tea grounds on feed intake, digestibility and ruminal fermentation characteristics of wethersANIMAL SCIENCE JOURNAL, Issue 2 2008Chuncheng XU ABSTRACT An experiment was conducted to examine feed intake, apparent digestibility, nitrogen balance, ruminal fermentation and blood components of wethers fed diets containing increasing levels of wet green tea grounds (WGTG). The experimental design was a 4 × 4 Latin square with four wethers in four 15-day periods. Wethers were allowed access to diets ad libitum, and allotted to one of four treatments in which WGTG replaced 0% (no WGTG added, CTG), 5% (low level, LBG), 10% (medium level, MTG), and 15% (high level, HTG) of total mixed ration (TMR) dry matter (DM) as wet brewers grains (WBG). All TMR silages were ensiled for 120 days and, irrespective of the WGTG addition, they were well preserved with a high lactic acid content, low pH and ammonia-N contents. There were no differences among treatments in feed intake, with the exception of ether extract intake (P = 0.032). Digestibilities for LTG and MTG treatments were not different from CTG. However, the organic matter, crude protein, acid detergent fiber and energy digestibilities for HTG treatment were lower than the CTG (P < 0.05). As the level of WGTG increased, nitrogen intake did not differ, but fecal nitrogen increased (P = 0.002), while urinary nitrogen decreased (P < 0.001). No differences among treatments were found in pH level and volatile fatty acids concentrations. However, the ruminal ammonia-N of the HTG silage was lower than for the CTG silage at all times (P < 0.05). Increasing concentrations of WGTG in the TMR silage decreased (P = 0.019) plasma urea nitrogen content. Therefore, the possible mixing proportion of WGTG for TMR silages can be 10% of the diet DM. [source] A factorially-designed study of physicochemical reactive dye colour removal from simulated cotton textile processing wastewatersCOLORATION TECHNOLOGY, Issue 5 2002G Carvalho The process performance of coagulation to remove reactive dyes from dyehouse effluent is affected by multiple factors, which can be best examined in factorially-designed experiments. A preliminary jar-test procedure was used to select coagulants and the optimal pH and coagulant dosage ranges. An inorganic salt (ferrous sulphate) and an organic polymer (DEC 50) were selected for further studies. Factorially-designed jar-test experiments were performed with different compositions of a synthetic cotton processing wastewater to determine which factors most affected colour removal and highlight interactions between them. Some additives, such as an oxidative desizing agent and a peroxide stabiliser, favoured colour removal within specific concentration ranges. The presence of sizing agents and surfactants reduced process efficiency. Increasing concentrations of ferrous sulphate could counteract this, but would result in higher sludge disposal costs. [source] Zinc and nitrate in the ground water and the incidence of Type 1 diabetes in FinlandDIABETIC MEDICINE, Issue 3 2004E. Moltchanova Abstract Aims In Finland, the risk of childhood Type 1 diabetes varies geographically. Therefore we investigated the association between spatial variation of Type 1 diabetes and its putative environmental risk factors, zinc and nitrates. Methods The association was evaluated using Bayesian modelling and the geo-referenced data on diabetes cases and population. Results Neither zinc nor nitrate nor the urban/rural status of the area had a significant effect on the variation in incidence of childhood Type 1 diabetes. Conclusions The results showed that although there was no significant difference in incidence between rural and urban areas, there was a tendency to increasing risk of Type 1 diabetes with the increasing concentration of NO3 in drinking water. The fact that no significant effect was found may stem from the aggregated data being too crude to detect it. [source] Consequences of hyperconcentrated flow for process-based soil erosion modelling on the Chinese Loess PlateauEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2006Rudi Hessel Abstract High sediment concentrations in runoff are a characteristic feature of the Chinese Loess Plateau, and are probably caused by factors such as the occurrence of erodible materials on steep slopes, the characteristics of the loess and the harsh climate that results in low plant cover. When sediment concentration increases, fluid density increases, viscosity increases and settling velocity decreases. These effects become increasingly important with increasing concentration and can result in flow behaviour that is quite different from that of clear water flow. Although the net effect of these changes on the flow is not always apparent, erosion models that deal with high sediment concentrations should consider such effects and could include corrections for some of these effects. A case study in a small catchment on the Loess Plateau indicated that sediment concentrations were considerable, and literature data suggested that for such sediment concentrations, corrections for settling velocity, fluid density and viscosity are needed. Furthermore, a number of corrections are necessary to be able to compare field measurements with results of soil erosion models: sediment volume should be subtracted from runoff volume and a density correction is needed to use data from a pressure transducer. For flumes that were used to measure discharge from smaller areas inside the catchment, the measured water level should be corrected by subtracting the sediment level in the flume from the water level, while the sediment volume should also be subtracted from the discharge. Finally, measured concentration should be corrected to give concentration expressed as grams per litre of clear water, since soil erosion models express sediment concentration in this way. Copyright © 2006 John Wiley & Sons, Ltd. [source] Voltammetric Analysis of Trace Levels of Platinum Group Metals , Principles and ApplicationsELECTROANALYSIS, Issue 21 20072Article first published online: 4 OCT 200, Clinio Locatelli Abstract The compelling use of autocatalytic converters, containing platinum group metals (PGMs), has been the cause, in the environmental and biological matrices, of an increasing concentration of such metals. For this reason, in the last decade, the literature has reported several papers regarding analytical procedures for the determination of Pt(II), Pd(II) and Rh(III) in real samples, generally employing spectroscopic methods. The present review intends to highlight the contribution of the voltammetric techniques for the determination of these metals, including also those less investigated, i.e. Iridium, Osmium and Ruthenium. [source] Capillary electrophoretic and computational study of the complexation of valinomycin with rubidium cationELECTROPHORESIS, Issue 5 2009Sille Ehala Abstract This study is focused on the characterization of interactions of valinomycin (Val), a macrocyclic dodecadepsipeptide antibiotic ionophore, with rubidium cation, Rb+. Capillary affinity electrophoresis was employed for the experimental evaluation of the strength of the Val,Rb+ complex. The study involved the measurement of the change of effective electrophoretic mobility of Val at increasing concentration of Rb+ cation in the BGE. From the dependence of Val effective electrophoretic mobility on the Rb+ cation concentration in the BGE (methanolic solution of 100,mM Tris, 50,mM acetic acid, 0,1,mM RbCl), the apparent binding (stability) constant (Kb) of the Val,Rb+ complex in methanol was evaluated as log,Kb=4.63±0.27. According to the quantum mechanical density functional theory calculations employed to predict the most probable structure of Val,Rb+ complex, Val is stabilized by strong non-covalent bond interactions of Rb+ with six ester carbonyl oxygen atoms so that the position of the "central" Rb+ cation in the Val cage is symmetric. [source] Influence of sediment ingestion and exposure concentration on the bioavailable fraction of sediment-associated tetrachlorobiphenyl in oligochaetes,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2008Arto J. Sormunen Abstract The desorption and bioavailability of 3,3,,4,4,-tetrachlorobiphenyl (PCB 77) were studied in spiked natural sediments at six concentrations. The desorption kinetics were measured in a sediment,water suspension using Tenax® resin extraction, and the bioavailability was measured by exposing Lumbriculus variegatus (Oligochaeta) to PCB 77,spiked sediment in a 14-d kinetic study. In addition, freely dissolved pore-water concentrations were measured using the polyoxymethylene solid-phase extraction method. The present study examined whether bioavailability can be defined more accurately by measuring the size of desorbing fractions and the pore-water concentrations than by using the standard equilibrium partitioning approach. The importance of ingested sediment in bioaccumulation also was investigated. Our data showed a clear, decreasing trend in the rapid-desorbing fractions and in the standard biota,sediment accumulation factors (BSAF) with increasing concentration in sediment. Desorbing fractions,refined BSAFs were more uniform across the concentration treatments, and the pore-water PCB 77 concentration predicted tissue concentrations close to observed values. In the risk assessment process, pore-water concentration or desorbing fractions would lead to more precise bioavailability estimates compared with those from the traditional equilibrium partitioning approach. The result also showed, however, that sediment-ingesting worms had access to an additional bioavailable chemical fraction that was especially evident when PCB 77 pore-water concentrations most likely approached the solubility limit. Thus, feeding may modify the bioavailable fraction that cannot be explained by simple equilibrium partitioning models. [source] Potential Bioelectroactive Bone Regeneration Polymer Nanocomposites with High Dielectric Permittivity,ADVANCED ENGINEERING MATERIALS, Issue 10 2009Zhi-Min Dang The frequency dependence of the dielectric permittivity of (barium titanate,hydroxyapatite)/poly(vinylidene fluoride) three-phase nanocomposites is investigated at room temperature and different fractions of barium titanate. The permittivity increases with increasing concentration of barium titanate. A weak decrease in permittivity is also observed for frequencies below 106 Hz. The SEM image inset in a dielectric permittivity vs. frequency curve shows that rod-like hydroxyapatite and sphere-like barium titanate nanoparticles exist in the three-phase nanocomposites. [source] Increased Concentration in Banking: Megabanks and Their Implications for Deposit InsuranceFINANCIAL MARKETS, INSTITUTIONS & INSTRUMENTS, Issue 1 2005Kenneth D. Jones During the past two decades, the U.S. banking industry has experienced an unprecedented wave of consolidation, marked by a substantial decline in the number of insured depository institutions and the emergence of banking behemoths with assets totaling in the hundreds of billions of dollars. This unparalleled concentration of assets and deposits among a handful of "megabanks" has important implications for deposit insurance. Most importantly, the Federal Deposit Insurance Corporation (FDIC) now faces a situation in which the failure of even a single megabank could overwhelm the resources immediately available to the deposit insurance system and expose both the banking industry and the government (i.e., taxpayers) to huge potential liabilities. This article highlights the current structure of the banking industry, examines the threat that this structure poses to the deposit insurance funds, and suggests possible approaches for dealing with megabanks and the increasing concentration of insured deposits. [source] Nanostructures, Optical Properties, and Imaging Application of Lead-Sulfide Nanocomposite CoatingsINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2004Song Wei Lu Lead-sulfide (PbS) nanocrystals were precipitated in nanocomposite coatings after a pre-photo-polymerization followed by a reaction with H2S gas at 25°C for 1 hr. PbS nanocrystalline size and optical absorption increased with decreasing UV energy for pre-photo-polymerization and increasing concentration. The absorption onset has a large blue shift from 0.41 eV of the corresponding bulk crystal, resulting from the quantum confinement effect. As a result, coating color changes significantly from deep brown to light yellow depending on coating processing conditions. Partially masking the coatings during pre-photo-polymerization gives rise to different colors, leading to imaging applications of PbS nanocomposite coatings. [source] Effect of self-assemblies of various surfactants in their single and mixed states on the BZ oscillatory reactionINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2010Muzaffar Hussain Najar Micelles of different surfactants are well known to affect chemical equilibria and reactivities by selectively sequestering the reagent substrates through electrostatic and hydrophobic interactions. In this article, the effects of micelles of various surfactants on different parameters of the Ce(IV)-catalyzed Belousov,Zhabotinsky (BZ) oscillatory reaction at 35°C in nonstirred closed conditions are studied by employing spectrophotometry and tensiometry. Surfactants used in this study are the cationics hexadecyltrimethylammonium bromide (CTAB) and pentamethylene-1,5-bis(N -hexadecyl- N,N -dimethylammonium)bromide gemini (Gemini), anionic sodium dodecylbenzene sulfonate (SDBS), and nonionic Brij58, whereas the binary surfactant systems used are cationic,nonionic CTAB+Brij58 and anionic,nonionic SDBS+Brij58. The results revealed that the induction period shows a definite variation with increasing concentration of different surfactants above their critical micelle concentration (cmc). The amplitudes of oscillation and absorbance maxima and minima are enhanced in the presence of micelles of CTAB and Gemini surfactants, whereas micelles of SDBS and Brij58 have almost no effect on the nature of the oscillations. However, mixed micelles of CTAB+Brij58 and SDBS+Brij58 binary mixtures show a quite different effect on the overall behavior of the oscillations. The enhanced effect of CTAB and Gemini surfactants on the overall nature of oscillations has been attributed to the positive charge on the surface of their micelles and to some extent on the presence of nitrogen in their head group. The effect of mixed binary micelles may be attributed to their synergistic nature. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 659,668, 2010 [source] Antioxidant activities of red pepper (Capsicum annuum) pericarp and seed extractsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2008Ki Hyeon Sim Summary In this study, we examined the antioxidant activities of red pepper (Capsicum annuum, L.) pericarp and red pepper seed extracts. The extracts were evaluated by various antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, superoxide anion radical scavenging, hydroxyl radical scavenging, [2,2,-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] (ABTS) radical scavenging, ferrous chelating activity, superoxide dismutase (SOD) activity and reducing power, along with the determination of total phenolic and flavonoid contents. All the extracts showed strong antioxidant activity by the testing methods. The red pepper pericarp extract exhibited strong ferrous chelating activity and high scavenging activity against free radicals, including both the hydroxyl and DPPH radicals, but it exhibited weaker scavenging activity for the superoxide anion radical and for SOD. In contrast, the red pepper seed extract exhibited strong SOD activity and high scavenging activity against the superoxide anion radical, but showed weaker ferrous chelating activity, hydroxyl radical scavenging, and DPPH radical scavenging. We observed that the reducing power level and ABTS radical scavenging activity of the red pepper seed were higher than those of the red pepper pericarp at the highest tested concentration. Most of the test results for the red pepper seed and red pepper pericarp extracts increased markedly with increasing concentration; however, the metal chelating, SOD and ABTS radical scavenging activities did not increase with the concentration. Highest total phenolic and flavonoid contents were obtained from the red pepper pericarp extracts. Overall, the red pepper seed and red pepper pericarp extracts were highly effective for the antioxidant properties assayed, with the exceptions of ferrous chelating activity, hydroxyl radical scavenging and SOD activity. [source] The UK air inclusive-tour industry: a reassessment of the competitive positioning of the ,independent' sectorINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 6 2001Nigel G. Evans Abstract This paper investigates the increasing concentration in the UK air inclusive-tour (AIT) market and the behaviour of the dominant companies (Thomson, Airtours, First Choice and Thomas Cook) operating in the sector. Arguments relating to the theoretical organisational structure of the industry are explored and regulatory investigations that have taken place are discussed. Research evidence as to the competitive position of independent tour operators in the overall UK AIT market is provided. The research indicates that a key area of difficulty for the independent sector relates to the provision of charter airline capacity although access to distribution channels and the ability to contract accommodation are viewed as further concerns. The paper concludes that regulatory authorities are faced with trying to ensure that diversity is maintained while at the same time ensuring any economies of scale derived from consolidation of the sector are passed on to consumers. In order to properly understand the true effects of industrial concentration the assembled package must be dissembled into its component parts and an increasingly a pan-European perspective is necessary. Copyright © 2001 John Wiley & Sons, Ltd. [source] Individual response of growing pigs to sulphur amino acid intakeJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1 2008J. Heger Summary Two N balance experiments were conducted to study the individual response of growing pigs to limiting amino acid (AA) intake. Series of fifteen diets with increasing concentration of sulphur amino acids (SAA, Expt 1) or methionine in the presence of excess cystine (Expt 2) were fed sequentially to nine pigs during a 15-day experimental period. The concentration of the AA under test ranged from 50% to 140% of the requirement while other essential AA were given in a 25% excess relative to the limiting AA. N retention was related to the limiting AA intake using rectilinear and curvilinear models. In Expt 1, the quadratic-plateau model fitted the individual data significantly better (p = 0.01) than the linear-plateau model. No difference was found between the two models in Expt. 2, presumably due to the sparing effect of excess cystine on methionine utilization. Exponential, saturation kinetics or four-parameter logistic models fitted to data for all pigs showed that their goodness of fit was similar to those of quadratic-plateau or linear-plateau models. Significant differences (p < 0.05) were found between individual plateau values for N retention within each experiment while the slopes of the regression lines did not significantly differ either in Expt 1 (p = 0.07) or Expt 2 (p = 0.45). There was a positive correlation between the slope and plateau values of the linear-plateau model in Expt 1 (r = 0.74, p = 0.02) but no significant correlation was found in Expt 2 (r = ,0.48, p = 0.13). Marginal efficiencies of SAA and methionine utilization derived from the linear-plateau model were 0.43 and 0.65 respectively. Based on linear-plateau and quadratic-plateau models, daily requirements of SAA and methionine for a 50 kg pig were estimated to be 13.0 and 5.9 g and 14.3 and 6.1 g respectively. [source] Using anionic polymerizable surfactants in ultrasonically irradiated emulsion polymerization to prepare polymer nanoparticlesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Yuhui He Abstract An ionic polymerizable surfactant, sodium sulfopropyl-laurylmaleate (M12), was synthesized and used as an emulsifier, an initiator, and a comonomer in ultrasonically irradiated emulsion polymerization. FTIR spectra and gravimetric method results indicated that copolymers P(Styrene-M12) and P(Butylacrlate-M12) were prepared successfully by ultrasonically irradiated emulsion polymerization and the composition of M12 elevated with the increasing concentration of M12 added. TEM photographs of P(St-M12) showed that the nanoparticles with small diameters (20,45 nm) were prepared. With the increase of M12 concentration, the particle size became smaller and the size distribution became wider. The P(BA-M12) particles size was also small (<100 nm) but the size distribution was wide due to the high reactivity of BA. Because surfmer M12 was chemically bonded with the latex particles, the stability of the copolymer latex prepared by ultrasonically irradiated emulsion polymerization was much better than that of the homopolymer latex (PSt or PBA) prepared by the same way. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Ozonation of 1,3,6-naphthalenetrisulfonic acid in presence of heavy metalsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2004M Sánchez-Polo Abstract A study was conducted of the mechanisms by which heavy metals, commonly present in industrial effluents, increase the purification effectiveness of ozone in the removal of organic contaminants of low biodegradability. For this purpose, the ozonation of 1,3,6-naphthalenetrisulfonic acid (NTS) in the presence of Ni(II), Fe(II), Mn(II), Zn(II), Sr(II), Cr(III), Cd(II), Hg(II), and Cu(II) was examined. The presence of small amounts of Mn(II), Fe(II), Ni(II), Zn(II), and Cr(III) was observed in the system, increasing the degradation rate of the NTS and transforming the dissolved organic matter into CO2. The mineralization of the organic matter was highly favored, especially in the first minutes of treatment. The results obtained appear to indicate that the activity of the metals in the NTS ozonation process is related to their reduction potential. Thus, metals susceptible to oxidation by ozone are potential promoters of NTS ozonation. The presence of Fe(II) or Mn(II) during NTS ozonation increased its degradation rate by 79% and 72% respectively. Moreover, the reaction kinetics of metal oxidation with ozone controls the increase in the purification effectiveness of these systems. The presence of radical scavengers (tert -butanol or bicarbonate) in the medium during the promoted ozonation of NTS showed a negative effect on this process, and the NTS degradation rate decreased with an increasing concentration of these inhibitors in the system. These results confirm that the degradation of NTS by ozone in the presence of heavy metals occurs by a radical mechanism. O3/Zn(II) and O3/Fe(II) systems were applied to the decontamination of urban waste waters. The presence of Zn(II) or Fe(II) during the ozonation produced a reduction during the first 5 min of treatment of 20% or 44%, respectively, in the concentration of dissolved organic matter present in the system. These results show that ozonation in the presence of heavy metals is a highly promising system for the purification of waste waters and industrial effluents. Copyright © 2004 Society of Chemical Industry [source] Thiol-mediated degradation of DNA adsorbed on a colloidal gold surfaceJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2003Shalu Mittal Abstract When [32P]-labeled DNA is adsorbed on colloidal gold from a 130,mmol,dm,3 solution of KH2PO4, it can subsequently be eluted with cold DNA without undergoing detectable degradation. Similarly, DNA can be incubated in solution in the presence or absence of colloidal gold with high concentrations of ,-mercaptoethanol or hexane-1-thiol without significant degradation. However, when adsorbed DNA is eluted from gold with solutions of one of the thiols, it is recovered as a mixture of mononucleotides and short oligomers. The extent of degradation increases with increasing concentration of the thiol and with increasing elution temperature. Our results emphasize that in designing protocols involving DNA adsorbed on gold surfaces, it is important to avoid allowing the DNA to come into contact with even moderate concentrations of thiols. © 2003 Society of Chemical Industry [source] Production of salmonid amoebic gill disease by exposure to Paramoeba sp. harvested from the gills of infected fishJOURNAL OF FISH DISEASES, Issue 2 2001D Zilberg Atlantic salmon, Salmo salar L., were exposed to different concentrations of Paramoeba sp. The lowest concentration which induced amoebic gill disease (AGD) was 230 Paramoeba sp. L,1 and the severity of infection increased with increasing concentration. The concentration of Paramoeba sp. positively correlated with the number of gill lesions (R2 > 0.7). This study provides evidence that Paramoeba sp. is the causative agent of AGD and describes an experimental model that enables the severity of the induced disease to be controlled. [source] Theoretical studies on structural and electrical properties of PES/SPEEK blend nanofiltration membraneAICHE JOURNAL, Issue 8 2009A. F. Ismail Abstract Polyethersulfone (PES) nanofiltration membranes were prepared using a simple dry-jet wet spinning technique with different contents of sulfonated poly(ether ether ketone) (SPEEK) ranging from 0 to 4 wt %. The structural parameters (rp and Ak/,x) and electrostatic properties (, and X) of the blend membranes were deduced by employing the combination of irreversible thermodynamic model, steric hindrance pore (SHP) model, and Teorell-Meyer-Sievers (TMS) model. The modeling results obtained have been analyzed and discussed. The mean pore radius and pore size distribution of the blends were also determined based on the theoretical models. The results showed that pore radius increased with increasing the concentration of SPEEK from 0 to 2 wt % but decreased with a further increase in SPEEK content. The water flux, however, showed a systematically increase with increasing SPEEK content. The SPEEK also showed significant effect on membrane electrical properties. Both effective charge density and ratio of effective charge density to electrolyte solution increased with increasing concentration of SPEEK in the dope solution, reaching a value of ,21.02 and ,2.29, respectively. The pore radius which was determined by using different transport models has also been analyzed and discussed. It is found that the addition of SPEEK into dope solution is one of the paramount parameters in developing the negatively charged nanofiltration membrane with enhanced water flux while retaining the pore radius in the nanometer range. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Preparation and characterization of polymethacrylate monolithic capillary columns with dual hydrophilic interaction reversed-phase retention mechanism for polar compoundsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15-16 2009í Urban Abstract Monolithic columns for capillary hydrophilic interaction liquid chromatography (HILIC) were prepared in fused-silica capillaries by radical co-polymerization of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide and ethylene dimethacrylate in various binary and ternary porogen solvent mixtures with azobisisobutyronitrile as the initiator of the polymerization reaction. Columns showed mixed separation modes: reversed-phase (RP) in water-rich mobile phases and HILIC at high concentrations of acetonitrile (>60,80%) in aqueous,organic mobile phases. A continuous change in retention was observed at increasing concentration of water in acetonitrile, giving rise to characteristic U-turn plots of retention factors versus the concentration of water in the mobile phase, with minima corresponding to the transition between the mechanisms controlling the retention. The selectivity of organic polymer monolithic columns for HILIC separations can be varied by adjusting the concentration of sulfobetaine monomer and the composition of the porogen solvent in the polymerization mixture. Under HILIC conditions, the monolithic capillary sulfobetaine columns show separation selectivities for polar phenolic acids similar to those of a commercial silica-based sulfobetaine ZIC-HILIC column, which, however, has limited selectivity in the RP mode due to lower retention. [source] THE USE OF TOMATO PULP POWDER AS A THICKENING AGENT IN THE FORMULATION OF TOMATO KETCHUPJOURNAL OF TEXTURE STUDIES, Issue 2 2008A. FARAHNAKY ABSTRACT In this current study, tomato pulp powder, the main waste of the tomato processing industry, was used as a thickening agent in the formulation of a commercial tomato ketchup at different levels (1, 2, 5, 7 and 10% w/w). Color parameters (L and a/b) and rheologic properties of the formulated ketchups with and without added tomato pulp powder were determined and compared. The addition of the pulp powder caused a significant increase in the L value of the samples, while a/b ratio decreased notably. The rheologic data obtained were fitted using a power law equation. The analysis of the data obtained revealed that low levels of tomato pulp powder can compete with other hydrocolloids in improving the consistency of tomato ketchup. All ketchup samples in this study were non-Newtonian fluids and the apparent viscosity of the ketchups increased significantly with increasing concentration of tomato pulp powder and decreased with temperature increase. Chemical composition (protein, total fat, reducing and total sugars, fiber, ascorbic acid and ash contents) and some physicochemical properties of the tomato pulp powder, including water absorption and solubility, were determined and the data were used for the interpretation of the rheologic and color changes as a result of the inclusion of the pulp powder in the formulation. PRACTICAL APPLICATIONS The direct use of food industry wastes in food formulations can help in reducing the production costs by decreasing raw material and disposal costs. The classic design of the tomato processing plants results in generating a large amount of tomato pulp. The results of this research confirmed that tomato pulp powder can be used instead of other hydrocolloids in tomato-based products. The reuse of tomato pulp powder in foods can be beneficial to producers and the environment. [source] Comprehensive Linkage of Defect and Phase Equilibria through Ferroelectric Transition Behavior in BaTiO3 -Based Dielectrics: Part 1.JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2008Defect Energies Under Ambient Air Conditions Defect and phase equilibria have been investigated via the ferroelectric phase transition behavior of pure and equilibrated nonstoichiometric BaTiO3 powder samples. Through fabricating the BaTiO3 materials under highly controlled conditions to preserve the equilibrium conditions with respect to Ba/Ti ratio, annealing temperature (T), and oxygen partial pressure (PO2), systematic variations in the phase transition temperature can be noted with respect to Ba/Ti ratio and T. From the data extracted, we can then determine solubility limits. Equilibrating the defect reactions at the solubility limits provides a direct approach to identify and calculate the defect energetics. The phase transition temperature decreased with increasing concentration of the TiO2 partial-Schottky defects (BaTi1,,O3,2,) and the BaO partial-Schottky defects (Ba1,,TiO3,,), and showed discontinuous changes in the two-phase region. The formation enthalpy and entropy for the partial-Schottky defect reactions was evaluated to be 2.32±0.1 eV and 10.15±0.7 kB for the BaO partial-Schottky defect, and 2.89±0.1 eV and 8.0±1.5 kB for the TiO2 partial-Schottky defects equilibrated under air annealing conditions. [source] Purification of citrus limonoids and their differential inhibitory effects on human cytochrome P450 enzymesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2007Shibu M Poulose Abstract Recent studies demonstrated that citrus limonoids and flavonoids possess numerous health promoting properties. In the present study, glucosides of limonoids and flavonoids were purified from citrus molasses and limonoid aglycones from citrus seeds. Glucosides were separated on styrene (divinylbenzene), Q-sepharose resins with increasing concentration of sodium chloride. A pH-dependent cold precipitation was carried out for the isolation of naringin in large quantity. Major aglycones such as limonin and nomilin were isolated from seeds by direct crystallization and minor limonoids were purified by vacuum liquid chromatography. The structures of the isolated compounds were confirmed by NMR spectra. Individual limonoids were tested for O -dealkylase and hydroxylase activities of human cytochrome P450 (CYP) isoenzymes such as CYP1A2, CYP1B1, CYP3A4 and CYP19, using ethoxyresorufin, methoxyresorufin and dibenzylfluorescein as substrates. Partial to high inhibition of CYPs was observed in dose-dependent assays. Significant (P < 0.001) reductions in enzyme activities were observed with purified compounds above 2 µmol. Kinetic analyses indicated that limonin glucoside inhibited CYP19 competitively (IC50, 7.1 µ mol L,1), whereas Nomilinic acid glucoside inhibited it noncompetitively (IC50, 9.4 µ mol,1). Nomilinic acid glucoside was the most potent limonoid, with an overall IC50 of < 10 µ mol, for all the enzymes tested. The differential inhibition of CYPs can be ascribed to structural variations of the limonoid nucleus. Limonoid inhibition of key CYPs involved in carcinogenesis supports growing evidence that citrus limonoids act as anticancer agents. 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